UCI Health will see you now: Welcome to our new co-workers and patients from Fountain Valley, Lakewood, Los Alamitos and Placentia Linda! 

Dr. William Karnes, UCI Health gastroenterologist and colon cancer screening specialist

William E. Karnes, MD


Gastroenterology, Internal Medicine

Clinical Interests

colon cancer screening, early detection and prevention of colorectal neoplasia, high-risk families for colorectal cancer, gastrointestinal bleeding, general gastroenterology, gastroesophageal reflux disease (GERD), capsule endoscopy

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  • American Board of Internal Medicine, Gastroenterology
  • American Board of Internal Medicine, Internal Medicine
  • English
Medical School
University of MinnesotaM.D.
University of MinnesotaInternal Medicine
Mayo School of Graduate EducationResearch Fellowship in Gastroenterology
UCLA Medical CenterGastroentrology and Hepatology Fellowship
Professional Positions
  • Professor — Division of Gastroenterology & Hepatology, Department of Medicine, UCI School of Medicine
  • Director — High Risk Program and Colonoscopy Quality, UCI Health Digestive Health Institute
  • Fellow — American Gastroenterological Association
  • Member — American Association for Cancer Research
  • Member — American Association for the Advancement of Science
  • Member — American College of Physicians
  • Member — American Medical Association
  • Member — California Medical Association
Awards and Recognition
  • Physicians of Excellence, Orange County Medical Association – 2021
  • Best Doctors in America® — Gastroenterology, 2015, 2016
  • American Federation of Clinical Research Award, 1995
  • Young Scholar Award, World Congress of Gastroenterology, 1994
  • National Institutes of Health Fellowship Training grants, 1987-88 and 1990-92
  • Merck Fellowship Training Grant, 1987-88
More Information

Dr. William E. Karnes is a board-certified UCI Health gastroenterologist who specializes in disorders of the gastrointestinal tract, including colorectal cancer screening, gastrointestinal reflux disease (GERD), swallowing disorders, irritable bowel syndrome, peptic ulcers and esophageal disorders.

He performs colonoscopies, upper endoscopies and capsule endoscopies, and treats gastrointestinal bleeding, chronic diarrhea, constipation, bloating and bacterial problems in the small intestines.

Karnes earned his medical degree from the University of Minnesota Medical School in Minneapolis, where he completed a residency in internal medicine. He went on to complete a fellowship in molecular biology at Mayo Clinic in Rochester, Minn., and a fellowship in gastroenterology at the University of California, Los Angeles.

His research interests include colon cancer screening, risk assessment for colon cancer and artificial intelligence-assisted colonoscopy. He also conducts translational research on colon cancer prevention, with an emphasis on regular colorectal screening, especially among patients and families with a genetic risk for developing the disease.

Karnes sees patients in Orange, Irvine and Costa Mesa.

Speakers Bureau Topics

  • Celiac disease
  • Chronic diarrhea
  • Colon cancer screening, diagnosis and treatment
  • Colon cancer: genetic risk factors
  • Eosinophilic esophagitis
  • Gastroesophageal reflux disease (GERD)
  • H. Pylori and peptic ulcer disease
  • Small intestine bacterial overgrowth (SIBO)

UCI Health Chao Family Comprehensive Digestive Disease Center
101 The City Drive South, Building 22C
Orange, CA 92868
Fax: 855-813-0240
UCI Health Digestive Disease Center — Irvine
Gottschalk Medical Plaza
1 Medical Plaza Drive
Irvine, CA 92697
Phone: 888-717-4463
Fax: 855-813-0240
UCI Health — Costa Mesa
1640 Newport Blvd.
Costa Mesa, CA 92627
Phone: 949-398-1440
Fax: 844-965-9446